Casting metal is a fun-filled activity, even if it can be very dangerous if the method is not given the respect it deserves.
Casting with a casting machine
Casting silver differs from melting silver in that after silver is melted in a crucible, it is poured into a mold, and tool-worked into its final shape. When silver is cast, it is poured into a hollow mold which shapes the form of the metal.
The process is long, and includes drying the plaster mold in electric kiln for 20 hours.
Here is the information on the automatic casting machine at school. It is a very neat machine that uses vacuum pressure for casting:
Melting with crucible
Crucible melting in a workshop is usually performed in order to re-use scrap metals. it is done with a high-power torch, in a well-ventilated environment and with proper heat protection so you workshop won’t go up in flames.
Most crucial advice for melting metal is: Be in the moment! It is pretty hard to lose concentration when the casting torch is on full blast and you can feel the heat from the kiln, but it could happen. Before casting you have to be in the moment to gather your supplies:
- Water bowl filled with water for quenching
- honeycomb blocks for placing your crucible on a secure surface
- skamoflex blocks or other heatshield material for the table
- sturdy pliers
- Cast-iron mold.
- grip wise for holding the sides of the mold in place
- also you need oil for lubricating the mold.
- Crucible is the ceramic bowl-or spoon shaped object in which the metal is melted.
I do have to comment on the above picture that when silver is already in its pure form, which it most likely is since it’s already made into beads, there really is no need to use borax. Borax is needed when the origin of the silver is unclear, and if the silver has impurities. This could also mean human skin oils from use, or tarnish. Otherwise the over-use of borax could display itself in the cast metal. Luckily borax will deposit itself usually in the surface of the metal, and is easily removed with a brass brush.
Also note that the crucible needs to be glazed with borax to protect the crucible from the heat of the torch. This is what borax is definitely good for.
Here is also a video on the melting process.
Hope you enjoyed my blog post on casting and melting metal 🙂 And please send me questions and comments on the quality of my posts, I would greatly welcome them.